This proposal examines the effect of RO93877, a selective 5HT4 agonist, on gastrointestinal transit to analyze the effects of the drug on predominantly colonic transit with the aim of determining if the drug will be of use for chronic constipation. The study is completed. The study demonstrated that this novel benzofuran, 5HT4-agonist accelerated proximal colonic and overall colonic transit. It led to the development of a phase III multicenter study of this medication in constipation and constipation-predominant irritable bowel syndrome.